TWI634201B - Thermal conductive sheet and device using the same, and manufacturing method of thermal conductive sheet - Google Patents

Abstract

The present invention provides a thermally conductive sheet which is excellent in flexibility and excellent in thermal conductivity in the thickness direction. The thermally conductive sheet of the present invention contains a curable resin composition, a thermally conductive fiber, and thermally conductive particles, and has a compression ratio of 40% or more. Further, the amount of the thermally conductive particles filled is 70 vol% or less. The thermally conductive sheet of the present invention can fill the step between various heat sources and the heat dissipating member to improve the adhesion, thereby improving the thermal conductivity in the thickness direction of the sheet. Further, in the case where the thermally conductive sheet is used for a long period of time in a high temperature environment, since the adhesion is improved, the thermal resistance can be lowered.

Description

Thermal conductive sheet and device using the same, and manufacturing method of thermal conductive sheet

The present invention relates to a thermally conductive sheet that promotes heat dissipation of exothermic electronic components and the like.

With the further development of high performance of electronic equipment, the density and high mounting of semiconductor elements have been developed. Along with this, heat dissipation from the electronic components constituting the electronic device is more efficiently made important. In order to efficiently dissipate heat, the semiconductor is mounted on a heat sink such as a heat radiating fan or a heat sink via a heat conductive sheet. It is widely used in the industry as a heat conductive sheet in which a filler such as an inorganic filler is dispersed in polyfluorene oxide.

Such a heat dissipating member is required to further increase the thermal conductivity. Generally, for the purpose of high thermal conductivity, the filling ratio of the inorganic filler blended in the matrix is increased, thereby making a correspondence. However, if the filling rate of the inorganic filler is increased, the flexibility is impaired, or the filling rate of the inorganic filler is high, and the powder is dropped. Therefore, there is a limit in increasing the filling rate of the inorganic filler.

Examples of the inorganic filler include alumina, aluminum nitride, and aluminum hydroxide. Further, in the case of high thermal conductivity, scaly particles such as boron nitride or graphite, carbon fibers, and the like may be filled in the matrix. It depends on the anisotropy of the thermal conductivity of the scaly particles and the like. It is known that, for example, in the case of carbon fibers, it has a thermal conductivity of about 600 to 1200 W/mK in the fiber direction. In the case of boron nitride, it has a thermal conductivity of about 110 W/mK in the plane direction, and It has an anisotropy with a thermal conductivity of about 2 W/mK in a direction perpendicular to the plane direction.

Thus, the direction of the surface of the carbon fibers and the scaly particles is the same as the thickness direction of the sheet which is the direction of heat transfer. That is, by arranging carbon fibers and scaly particles in the thickness direction of the sheet, heat conduction can be dramatically improved. However, when a hardened hardened material is formed after the dicing, if the thickness cannot be cut to a uniform thickness, the uneven portion on the surface of the sheet is large, and air is interposed in the uneven portion, and the problem of excellent heat conduction is not exhibited.

In order to solve this problem, for example, Patent Document 1 proposes a heat-conductive rubber sheet which is formed by punching and cutting a knife which is arranged at equal intervals with respect to the longitudinal direction of the sheet. Further, in Patent Document 2, it is proposed to obtain a thermally conductive sheet having a specific thickness by cutting a laminate which is repeatedly coated and hardened by a cutting device having a circular rotary blade. Further, in Patent Document 3, it is proposed to use a metal saw to align the layer with a thickness of 0° with respect to the thickness direction of the sheet from which the expanded graphite sheet is obtained (at an angle of 90° with respect to the surface of the laminate). A layered body of a graphite layer containing anisotropic graphite particles is contained above the layer. However, in the cutting methods proposed by the above, there are problems in that the surface roughness of the cut surface is increased, the thermal resistance at the interface is increased, and the heat conduction in the thickness direction is lowered.

In recent years, the industry expects a thermally conductive sheet to be used between various heat sources (for example, various devices such as an LSI, a CPU, a transistor, and an LED) and a heat dissipating member. In order to fill the gap between the various heat sources and the heat dissipating members, the heat transfer sheets are closely contacted, and it is expected that the heat can be compressed.

In the thermally conductive sheet, the thermal conductivity of the sheet is usually increased by filling a large amount of the inorganic filler having thermal conductivity (for example, refer to Patent Documents 4 and 5). However, when the filling amount of the inorganic filler is increased, the sheet becomes hard and brittle. Further, for example, a large amount of a polyfluorene-based thermally conductive sheet filled with an inorganic filler is used for a long time. When placed in a high temperature environment, the heat conductive sheet becomes hard and the thickness becomes thick, and the thermal resistance of the heat conductive sheet rises when the load is applied.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-56299

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-50240

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-55021

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2007-277406

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2007-277405

The present invention has been made in view of such circumstances, and an object thereof is to provide a thermally conductive sheet which is excellent in flexibility and excellent in thermal conductivity in the thickness direction.

In order to solve the above problems, the thermally conductive sheet of the present invention is characterized in that it contains a curable resin composition, a thermally conductive fiber, and thermally conductive particles, and has a compression ratio of 40% or more.

Moreover, the thermally conductive sheet of the present invention is characterized in that it contains a curable resin composition, a thermally conductive fiber, and thermally conductive particles, and the amount of the thermally conductive particles and the thermally conductive fibers is 70 vol% or less.

Further, the apparatus of the present invention is characterized in that it is formed by sandwiching a heat conductive sheet between a heat source and a heat radiating member.

Since the thermally conductive sheet of the present invention has excellent flexibility, it can fill the step between various heat sources and the heat dissipating member to improve the adhesion, thereby improving the thermal conductivity in the thickness direction of the sheet. Moreover, when the thermal conductive sheet is used for a long time in a high temperature environment, the adhesion is improved, so Reduce thermal resistance.

1‧‧‧thermal sheet

2‧‧‧ Columnar thermal conductivity composition

3‧‧‧Supersonic cutting machine

4‧‧‧Supersonic Cutter

5‧‧‧Workbench

6‧‧‧Mobile Station

7‧‧‧ Polyoxyethylene rubber

8‧‧‧Mobile agencies

9‧‧‧Cutting knife

10‧‧‧Supersonic oscillator

11‧‧‧ Lifting mechanism

12‧‧‧ Thermal Conductive Composition

13‧‧‧Extrusion machine

14‧‧‧Preform

14A‧‧‧Layer

15‧‧‧Template

16‧‧‧Formal molded body

Fig. 1 is a flow chart for explaining an example of a method of producing a thermally conductive sheet of the present invention.

Fig. 2 is an external view showing an example of an ultrasonic cutting machine used in the cutting step in the method for producing a thermally conductive sheet of the present invention.

Fig. 3 is an external view showing an example of a cutting device.

Fig. 4 is a flow chart for explaining an example of the arrangement procedure in the method of manufacturing another thermally conductive sheet of the present invention.

Fig. 5 is a schematic view for explaining an example of a preforming step, an arranging step, and a formal forming step in the method for producing a thermally conductive sheet of the present invention.

Fig. 6 is a perspective view showing an example of a laminate obtained in the aligning step in the method for producing a thermally conductive sheet of the present invention.

In Fig. 7, (A) is a perspective view showing an example of a main molded body in which pressurization is not performed, and (B) is a perspective view showing an example of a main molded body subjected to pressurization.

Fig. 8 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber length is 50 μm.

Fig. 9 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber length is 100 μm.

Fig. 10 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber length is 150 μm.

Fig. 11 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber length is 180 μm.

Fig. 12 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber length is 250 μm.

Fig. 13 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 6:4.

Fig. 14 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 55:45.

Fig. 15 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 5:5.

Fig. 16 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 3:7.

Fig. 17 is a graph showing the thermal resistance with respect to the elapsed time in a state in which the thermally conductive sheet of Example 17 is sandwiched between the heat source and the heat dissipating member.

Fig. 18 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the load when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 55:45.

Fig. 19 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 55:45.

Fig. 20 is a graph showing the thermal resistance of the thermally conductive sheet with respect to the load when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 55:45.

Fig. 21 is a graph showing the thermal resistance of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 55:45.

Fig. 22 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the load when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 60:40.

Fig. 23 is a graph showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 60:40.

Fig. 24 is a graph showing the thermal resistance of the thermally conductive sheet with respect to the load when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 60:40.

Fig. 25 is a graph showing the thermal resistance of the thermally conductive sheet with respect to the compression ratio when the blend ratio of the polyxanthine main agent A to the hardener B (polyoxygen main component A: hardener B) is 60:40.

Hereinafter, embodiments of the present invention (hereinafter referred to as the present embodiment) will be described in detail in the following order with reference to the drawings.

Thermal sheet

2. Method for manufacturing heat conductive sheet

3. Another method of manufacturing a thermal conductive sheet

4. Examples

<1. Thermal sheet>

Hereinafter, the curable resin composition, the thermally conductive fiber, the thermally conductive particles, and the like constituting the thermally conductive sheet of the present embodiment will be described.

The thermally conductive sheet of the present embodiment contains a curable resin composition, a thermally conductive fiber, and thermally conductive particles, and has a compression ratio of 40% or more.

Further, the thermally conductive sheet of the present embodiment contains a curable resin composition and a thermally conductive fiber. Dimensions and thermally conductive particles, and the filling amount of the thermally conductive particles and the thermally conductive fibers is 70 vol% or less.

Specifically, the amount of the thermally conductive particles and the thermally conductive fibers is 70 vol% or less, and the liquid-phase polyoxynoxy resin having a two-liquid addition reaction of a polyxanthene main agent and a curing agent is used as the curability. In the case of the resin composition, the blend ratio of the polyxanthine main agent to the hardener (polyoxygen main agent: hardener) is set to 5:5 to 6:4, whereby the compressibility of the thermally conductive sheet can be set. It is 40% or more.

Since the compressibility of the thermally conductive sheet is 40% or more, the step difference between the various heat sources and the heat dissipating member can be filled to improve the adhesion, thereby improving the thermal conductivity in the thickness direction of the sheet. Further, in the case where the thermally conductive sheet is used for a long period of time in a high temperature environment, the adhesion is improved, so that the thermal resistance can be lowered.

Further, when the compression ratio is 40% or less, the thermally conductive sheet preferably has a peak of thermal conductivity of 15 W/mK or more, and more preferably has a peak of thermal conductivity of 20 W/mK or more. Thereby, excellent thermal conductivity can be obtained in a compressed state in which a load is applied to the thermally conductive sheet.

Further, the thermally conductive sheet preferably has a heat resistance of 0.5 kgf/cm ² or more and a load range of 3 kgf/cm ² or less having a minimum value. That is, the heat-resistant sheet has a heat resistance value of 0.5 kgf/cm ² or more and a load range of 3 kgf/cm ² or less, which decreases as the applied load increases, and increases after the minimum value is obtained. In this case, for example, when a heat transfer sheet and a heat dissipation member are provided on a heat generating body such as an electronic component on a substrate, the heat generating body and the heat radiating member can be closely contacted with a small load, and excellent thermal conductivity can be obtained. Moreover, since it can be mounted on the substrate with a small load, the risk of damage of the substrate can be reduced.

Further, the thickness of the thermally conductive sheet is 3.0 mm or less, and the maximum compressive stress at 40% compression at a speed of 25 mm/min or less is preferably 1000 N or less. Since the maximum compressive stress is small, the load on the substrate is reduced at the time of installation, so that the risk of damage of the substrate can be reduced. Further, if the thickness of the thermally conductive sheet is thick and the compression speed is small, the maximum compressive stress is reduced.

Further, the thickness of the thermally conductive sheet is 3.0 mm or less, and the residual stress at 40% compression at a speed of 25 mm/min or less and maintained at 40% compression for 10 minutes is preferably 220 N or less. By the small residual stress, the stress applied to the substrate can be reduced during long-term use.

[Curable resin composition]

The curable resin composition is not particularly limited and may be appropriately selected depending on the properties required for the thermally conductive sheet. For example, a thermoplastic polymer or a thermosetting polymer can be used.

The thermoplastic polymer may, for example, be a thermoplastic resin, a thermoplastic elastomer, or a polymer blend of the above.

The thermoplastic resin is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include an ethylene-α-olefin copolymer such as polyethylene, polypropylene, and an ethylene-propylene copolymer; polymethylpentene, polyvinyl chloride, and the like. Polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyacetal, polyvinylidene fluoride, polytetrafluoroethylene and other fluorine resin; polyethylene terephthalate , polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyacrylonitrile, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS) resin, Polyphenylene ether, modified polyphenylene ether, aliphatic polyamine, aromatic polyamine, polyamidoximine, polymethacrylic acid or its ester, polyacrylic acid or its ester, poly Carbonate, polyphenylene sulfide, polyfluorene, polyether oxime, polyether nitrile, polyether ketone, polyketone, liquid crystal polymer, polyoxyn epoxide, ionic polymer, and the like. These may be used alone or in combination of two or more.

Examples of the thermoplastic elastomer include a styrene-based thermoplastic elastomer such as a styrene-butadiene copolymer or a hydrogenated polymer thereof, a styrene-isoprene block copolymer or a hydrogenated polymer thereof, and an olefin thermoplastic. Elastomer, vinyl chloride thermoplastic elastomer, polyester heat A plastic elastomer, a polyurethane-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, or the like. These may be used alone or in combination of two or more.

Examples of the thermosetting polymer include a crosslinked rubber, an epoxy resin, a polyimide resin, a bis-n-butylene imide resin, a benzocyclobutene resin, a phenol resin, and an unsaturated polyester. Diallyl phthalate resin, polyoxyn epoxide resin, polyurethane, polythene oxide polyfluorene oxide, thermosetting polyphenylene ether, thermosetting modified polyphenylene ether, and the like. These may be used alone or in combination of two or more.

Examples of the crosslinked rubber include natural rubber, butadiene rubber, isoprene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene rubber, chlorinated polyethylene, and chlorosulfonated polyethylene. , butyl rubber, halogenated butyl rubber, fluororubber, urethane rubber, acrylic rubber, polyisobutylene rubber, polyoxymethylene rubber, and the like. These may be used alone or in combination of two or more.

The curing method of the curable resin composition is not particularly limited, and may be appropriately selected depending on the properties required for the thermally conductive sheet. For example, a curing agent mixing type, a solvent volatilization type, a heat curing type, a hot melt type, an ultraviolet curing type, or the like may be used. .

In the present embodiment, it is preferable to use a curing agent-mixed polyoxynoxy resin from the viewpoint of excellent moldability and weather resistance, and adhesion to electronic components and followability. The polyoxymethylene resin is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include an addition reaction type liquid polyoxyxene rubber and a heat vulcanization type of a peroxide type (Millable type). Polyoxyethylene rubber, etc. Among these, as the heat dissipating member of the electronic device, the adhesion between the heat generating surface of the electronic component and the heat sink surface is required, and therefore, an addition reaction type liquid polyoxyxene rubber is preferable.

In the case of using a two-liquid addition reaction type liquid polyanthracene resin of a polyxanthine main agent and a hardener as a curable resin composition, a blend ratio of a polyxanthine main agent to a hardener (poly) The antimony main agent: hardener) is set to 5:5 to 6:4, whereby the compression ratio of the thermal conductive sheet can be set to 40% or more.

The content of the curable resin composition in the thermally conductive sheet is not particularly limited, and may be, for example, 25% by volume or more and 45% by volume or less.

[thermal fiber]

As the thermally conductive fiber, for example, carbon fiber can be used. As the carbon fiber, for example, a pitch system, a PAN system, an arc discharge method, a laser evaporation method, a CVD method (chemical vapor phase growth method), a CCVD method (catalytic chemical vapor phase growth method), or the like can be used. Among these, from the viewpoint of heat conduction, a pitch-based carbon fiber or a carbon fiber obtained by graphitizing polybenzazole is particularly preferable.

The pitch-based carbon fiber is obtained by subjecting asphalt as a main raw material to heat treatment at a high temperature of 2000 to 3000 ° C or more than 3000 ° C after various processing steps such as melt spinning, non-melting, and carbonization. The raw material pitch can be divided into an isotropic pitch which is optically disordered and does not exhibit a bias, and an anisotropic pitch (mesophase pitch) which constitutes a liquid crystal and which exhibits optical anisotropy. The carbon fiber produced from the anisotropic pitch is superior in mechanical properties to the carbon fiber produced from the isotropic pitch, and the electrical and thermal conductivity is increased. Therefore, it is preferred to use mesophase pitch-based graphitized carbon fibers.

The carbon fiber may be used by surface treatment of some or all of it as needed. Examples of the surface treatment include oxidation treatment, nitridation treatment, nitration, sulfonation, or attachment or bonding of a metal, a metal compound, an organic compound, or the like to the surface introduction by the treatment. Treatment of functional groups or surfaces of carbon fibers, and the like. Examples of the functional group include a hydroxyl group, a carboxyl group, a carbonyl group, a nitro group, and an amine group.

The average fiber length of the thermally conductive fibers is preferably 50 μm or more and 250 μm or less, and more preferably 100 μm or more and 250 μm or less. When the average fiber length of the thermally conductive fibers is 50 μm or more and 250 μm or less, the thermally conductive fibers are easily entangled with each other, and the thermal conductivity of the thermally conductive sheet in the thickness direction can be further improved. Further, in the state where the thermally conductive sheet is compressed, an excellent peak of the thermal conductivity can be obtained. Further, in order to adjust the average fiber length, carbon fibers having different average fiber lengths may be mixed. Further, the average fiber length of the thermally conductive fibers can be measured, for example, by a particle size distribution meter, a microscope, a scanning electron microscope (SEM), or the like. Further, the average diameter of the thermally conductive fibers is preferably 5 μm or more and 20 μm or less.

The content of the thermally conductive fibers in the thermally conductive sheet is preferably 15% by volume or more and 40% by volume or less. When the content of the thermally conductive fibers is 15% by volume or more, the thermal resistance value can be more effectively reduced, so that the thermal conductivity in the thickness direction of the thermally conductive sheet can be further improved. Moreover, by setting the content of the thermally conductive fibers to 40% by volume or less, for example, it is possible to prevent extrusion of the thermally conductive composition by the extruder.

[thermally conductive particles]

The thermally conductive particles can be used to easily align the thermally conductive fibers in a specific direction by the difference in flow velocity of the thermally conductive fibers in the thermally conductive composition, that is, to easily align the thermally conductive fibers in the extrusion direction. Further, the thermally conductive particles can also be used to maintain the shape of the thermally conductive sheet.

As the thermally conductive particles, for example, alumina, aluminum nitride, aluminum hydroxide, ceria, boron nitride, titanium oxide, glass, zinc oxide, tantalum carbide, silicon, cerium oxide, aluminum oxide, metal can be used. Particles, etc. These may be used alone or in combination of two or more. The Among the above, among the alumina, the aluminum nitride, and the aluminum hydroxide, it is preferred to use at least one or more of alumina.

The aluminum nitride has nitrogen in its molecule, and this nitrogen suppresses the reaction of the curable resin composition, and suppresses the increase in the viscosity of the thermally conductive composition. Therefore, by using aluminum nitride, the thermally conductive fibers can be more effectively aligned along the thickness direction of the thermally conductive sheet than when only the alumina particles as the thermally conductive particles are used, and the thickness direction of the thermally conductive sheet can be made. The thermal conductivity becomes good.

Further, the thermally conductive particles are preferably subjected to surface treatment with, for example, a decane coupling agent. By surface-treating the thermally conductive particles, the dispersibility can be improved, and the flexibility of the thermally conductive sheet can be improved. Moreover, the surface roughness obtained by cutting can be made smaller.

The average particle diameter of the thermally conductive particles is preferably 0.5 μm or more and 10 μm or less. When the average particle diameter is less than 0.5 μm, the curing failure may occur. When the average particle diameter exceeds 10 μm, the flexibility of the thermally conductive sheet may be lowered, and the thermal conductivity of the cured product may be lowered.

Further, by using two or more kinds of the thermally conductive particles, the thermally conductive fibers can be more easily aligned in the thickness direction of the thermally conductive sheet, and the thermal conductivity in the thickness direction of the thermally conductive sheet can be made better. . When two or more types of particle diameters are used as the thermally conductive particles, it is preferable that the larger spherical particles are 3 μm or more and 10 μm or less, and the smaller spherical particles are 0.3 μm or more. 3 μm or less. Thereby, the thermally conductive fibers can be more easily aligned in the thickness direction of the thermally conductive sheet, and the thermal conductivity in the thickness direction of the thermally conductive sheet can be improved. Further, the average particle diameter of the thermally conductive particles can be measured, for example, by a particle size distribution meter or a scanning electron microscope (SEM).

The content of the thermally conductive particles in the thermally conductive sheet is preferably 70% by volume or less, more preferably 20% by volume or more and 60% by volume or less. By setting the content of the thermally conductive particles to 70% by volume In the following, excellent flexibility can be obtained, and the thermal conductivity in the thickness direction of the thermally conductive sheet can be further improved.

Further, in the thermally conductive composition, for example, a solvent, a thixotropic imparting agent, a dispersing agent, a curing agent, a curing accelerator, a retarding agent, a microadhesive imparting agent, a plasticizer, a flame retardant, or the like may be blended as needed. Other ingredients such as antioxidants, stabilizers, colorants, etc.

Further, the thickness of the thermally conductive sheet is preferably 0.1 mm or more. If the thickness of the thermally conductive sheet is less than 0.1 mm, depending on the hardness of the cured product, there is a case where the shape cannot be maintained at the time of cutting. It is also possible to form a dot-like or linear adhesive layer on the outer periphery of the obtained sheet.

Preferably, the thermally conductive sheet is sandwiched between the heat source and the heat dissipating member. Examples of the heat source include an LSI, a CPU, a transistor, and an LED. Preferably, the heat transfer sheet is sandwiched between a communication LSI and a heat dissipating member, and the heat transfer sheet is sandwiched between the CPU and the computer. A computer between the heat dissipating members, etc.

Since the thermally conductive sheet of the present embodiment has excellent flexibility and the adhesion is improved over time, the thermal resistance of the thermally conductive sheet sandwiched between the heat source and the heat dissipating member can be reduced by 3% from the initial value. the above.

<2. Method of Manufacturing Thermal Sheet>

Next, a method of manufacturing the above thermally conductive sheet will be described. As shown in Fig. 1, the method for producing a thermally conductive sheet of the present embodiment includes a thermally conductive composition forming step S1, a molding step S2, and a cutting step S3.

[Thermal composition preparation step S1]

In the thermally conductive composition producing step S1, the thermally conductive composition is prepared by mixing a curable resin composition, a thermally conductive fiber, and thermally conductive particles with a stirrer or the like. Preferably, for example, the blending amount of the thermally conductive fiber and the thermally conductive particles in the thermally conductive sheet forming composition is set to 16 to 40% by volume and 30 to 60% by volume, the thermally conductive fibers are carbon fibers having an average diameter of 5 to 20 μm and an average fiber length of 50 to 250 μm.

[Molding step S2]

In the molding step S2, the thermally conductive composition produced in the thermally conductive composition production step S1 is extrusion-molded in a mold using a pump, an extruder or the like to obtain a columnar cured product. The shape, the size, the material, and the like are not particularly limited as the mold, and may be appropriately selected depending on the purpose. Examples of the shape include a hollow column shape and a hollow column shape. The size can be appropriately selected depending on the size of the thermally conductive sheet to be produced. Examples of the material include stainless steel and the like.

The extrusion-molded forming system is made into a cured product by a suitable hardening reaction depending on the resin to be used. The method of curing the extrusion molded body is not particularly limited, and may be appropriately selected depending on the purpose. For example, when a thermosetting resin such as a polyoxyxylene resin is used as the curable resin composition, it is preferably cured by heating.

Examples of the apparatus for heating include a far infrared furnace, a hot air furnace, and the like. The heating temperature is not particularly limited and may be appropriately selected depending on the purpose, and is preferably carried out, for example, at 40 ° C to 150 ° C. The softness of the cured product is not particularly limited and may be appropriately selected depending on the purpose, and may be adjusted, for example, according to the crosslinking density of polyfluorene oxide, the filling amount of the thermally conductive filler, and the like.

Thereby, for example, as shown in FIG. 2, a columnar thermally conductive composition in which the thermally conductive fibers are aligned in the longitudinal direction L of the columnar shape can be formed. In the process of passing the thermally conductive composition through the die by an extruder or the like, the thermally conductive fibers, the thermally conductive particles, and the like are concentrated in the center direction of the thermally conductive composition, and the density of the thermally conductive fibers at the surface and the center is different. . In other words, in the surface of the heat-conducting composition (molded body) of the extruder, the thermally conductive fiber does not protrude from the surface, so that the surface portion of the cured product obtained by hardening the thermally conductive composition (molded body) (the outer periphery of the thermally conductive sheet) The part has good adhesion and good adhesion to the adherend (semiconductor device, etc.). On the other hand, since the surface in contact with the heat source or the heat radiating side protrudes due to the heat conductive fiber, the microadhesiveness is lowered.

Here, the term "microadhesive property" refers to a re-peelability having a small increase in adhesion caused by aging and moist heat, and has a degree that the position is not easily offset when attached to a member to be bonded. Adhesion.

Further, in the molding step S2, for example, the thermally conductive composition produced in the thermally conductive composition production step S1 is applied onto the polyester film coated with the release material to form a columnar shape as shown in FIG. Thermal conductivity composition.

[Cutting Step S3]

The cutting step S3 is a step of cutting the columnar cured material into a specific thickness in a direction substantially perpendicular to the longitudinal direction of the column. For example, as shown in FIG. 2 and FIG. 3, the ultrasonic heat cutting device 3 is used to cut the columnar heat conduction by the ultrasonic cutter 4 in the direction V orthogonal to the longitudinal direction L of the columnar thermally conductive composition 2. The composition 2 can thereby form the thermally conductive sheet 1 while maintaining the alignment of the thermally conductive fibers. Therefore, the alignment of the thermally conductive fibers is maintained in the thickness direction, and the thermally conductive sheet 1 having good thermal conductivity can be obtained.

In the cutting step S3, it is preferable to cut into a specific thickness, and the maximum compressive stress at 40% compression at a speed of 25 mm/min or less is 1000 N or less. Further, in the cutting step S3, it is preferable to cut into a specific thickness and to perform 40% compression at a speed of 25 mm/min or less, and to maintain a residual stress of 220 N or less in a state of 40% compression for 10 minutes. Further, in the cutting step S3, it is preferable to cut into a specific thickness so that the heat resistance is 0.5 kgf/cm ² or more and the load range of 7.5 kgf/cm ² or less becomes 2.0K. Cm ² /W or less. Moreover, in the cutting step S3, it is preferable to cut into a thickness of 3.0 mm or less. Thereby, a thermally conductive sheet which is excellent in flexibility, repulsive force, and excellent in followability to a portion to be provided can be obtained.

As shown in FIG. 3, the ultrasonic cutting machine 3 includes a table 5 on which a columnar thermally conductive composition 2 is placed, and an ultrasonic cutter 4 that applies ultrasonic vibration on one side to face the table 5 The columnar thermal conductive composition 2 is cut.

In the table 5, a polyoxyn rubber 7 is disposed on the metal moving table 6. The moving table 6 is movable in a specific direction by the moving mechanism 8, and sequentially performs the transfer operation of the columnar thermally conductive composition 2 to the lower portion of the ultrasonic cutter 4. The polyoxyxene rubber 7 has a thickness sufficient to withstand the tip of the ultrasonic cutter 4. When the columnar thermal conductive composition 2 is placed on the polysulfide rubber 7, the movable table 6 is moved in a specific direction by the cutting operation of the ultrasonic cutter 4, thereby sequentially thermally conducting the columnar shape. The sexual composition 2 is delivered to the lower portion of the ultrasonic cutter 4.

The ultrasonic cutter 4 has a cutting blade 9 that cuts the columnar thermally conductive composition 2, an ultrasonic oscillation mechanism 10 that imparts ultrasonic vibration to the cutting blade 9, and an elevating mechanism 11 that is opposed to the cutting blade 9. Carry out the lifting operation.

The cutting blade 9 is directed toward the table 5, and is lifted and lowered by the lifting mechanism 11, whereby the columnar thermally conductive composition 2 placed on the table 5 is cut. The cutter 9 can use a single or double knife capable of ultrasonic oscillation. Regarding the double knives, if the double knives are cut perpendicularly to the molded body, the thickness of the cut sheet is inclined in the plane, so it is necessary to make the double knives perpendicular to the formed body so that the double knives are doubled. The knife is tilted. The slope becomes the angle of half the angle of the tip of the double knife. The size or material of the cutting blade 9 is determined according to the size or composition of the columnar thermally conductive composition 2, for example, the cutting blade 9 is made of a width of 40 mm and a thickness. 1.5mm steel with a tip angle of 10°. Then, after the obtained molded body is hardened, it is cut perpendicularly to the hardened blade, whereby the thickness can be cut into a uniform thickness, and the surface roughness of the cut surface can be reduced, so that an interface can be produced. The thermal resistance of the sheet is lowered, and the heat conduction sheet having a higher heat conduction in the thickness direction of the sheet is used. Further, the surface roughness Ra can be measured, for example, by a laser microscope.

The ultrasonic oscillating mechanism 10 applies ultrasonic vibration to the dicing blade 9 in the cutting direction of the columnar thermally conductive composition 2, and preferably has an oscillation frequency of 10 kHz to 100 kHz and an amplitude of 10 μm to 100 μm. Adjustment.

The thermal conductive sheet 1 which is cut while imparting ultrasonic vibration by the ultrasonic cutting machine 3 is suppressed to have a lower thermal resistance than the thermally conductive sheet 1 which is not subjected to ultrasonic vibration. Since the ultrasonic cutter 3 imparts ultrasonic vibration to the cutting direction in the ultrasonic cutting device 4, the thermal conductive fibers having a low interface thermal resistance and aligned in the thickness direction of the thermal conductive sheet 1 are less likely to be knocked down by the cutting blade 9. On the other hand, in the thermally conductive sheet which is not subjected to ultrasonic vibration and is cut by the frictional resistance of the dicing blade, the alignment of the thermally conductive fibers is disturbed, and the exposure to the cut surface is reduced, so that the thermal resistance is increased. Therefore, by using the ultrasonic cutter 3, the thermally conductive sheet 1 excellent in thermal conductivity can be obtained.

The formed body thus finished by the hardening reaction is cut into a specific thickness in a direction perpendicular to the extrusion direction, whereby a thermally conductive sheet in which the thermally conductive fibers are aligned (vertical alignment) in the thickness direction of the thermally conductive sheet can be obtained. The thickness of the thermally conductive sheet is preferably 0.1 mm or more. When the thickness is less than 0.1 mm, depending on the hardness of the cured product, the shape cannot be maintained at the time of cutting. Further, at the time of cutting, the formed body may be cut while being subjected to temperature adjustment such as cooling or heating. Alternatively, the knife can be cut while cooling the blade.

Further, it further has a pressurizing step of pressurizing the thermally conductive sheet formed by cutting in a substantially vertical direction, and preferably pressurizing in a pressurizing step to have a thermal resistance of 0.5 kgf/cm ² or more and 7.5 kgf / The load range below cm ² becomes 2.0K. Cm ² /W or less. Further, in the pressurizing step, it is preferred to pressurize at a pressure of 0.1 MPa or more and 30 MPa or less. Further, in the pressurizing step, it is preferred to pressurize at a temperature of from room temperature to 140 ° C. In the case of pressurizing the thermally conductive sheet, it is considered that since the density is increased and hardened due to the compression, the maximum compressive stress is increased, but the maximum compressive stress can be reduced by pressurizing under the above-mentioned pressurized conditions. . The reason for this is considered to be that the oil component in the thermally conductive sheet is oozing out to the surface of the sheet by pressure, and the sliding property is improved, and the maximum compressive stress is reduced.

<3. Method of Manufacturing Another Thermal Sheet>

The thermally conductive sheet 1 can be produced by the manufacturing method shown below. That is, as shown in FIG. 4, in the molding step S2 of the method for manufacturing the thermally conductive sheet, a preforming step S21, an arranging step S22, and a forming step S23 may be included. In the following description, the thermal conductive composition preparation step S1 and the cutting step S3 are omitted, and detailed description thereof will be omitted.

[Preforming step S21]

In the preforming step S21, as shown in FIG. 5(A), the thermally conductive composition 12 produced in the thermally conductive composition production step S1 is extruded by the extruder 13, and the thermally conductive fibers are extruded along the extrusion direction. The elongated columnar preform 14 (hereinafter referred to as a preform 14) which is aligned is molded.

For example, as shown in Fig. 5(A), the extruder 13 is formed in a tubular shape having an elongated shape, and the diameter W2 of the opening portion 12B on the side where the heat conductive composition 12 is discharged is preferably smaller than that in the body portion 12A. The diameter W1 is reduced. Further, in the extruder 13, the inner diameter W1 of the main body portion 12A is from the long side direction. The specific position is reduced to a tapered shape toward the extrusion direction, and the diameter W2 of the opening portion 12B can be reduced compared to the inner diameter W1 of the main body portion 12A. The thermally conductive composition 12 is extruded by the extruder 13 to pass the thermally conductive composition 12 in the extruder 13 toward a portion having a smaller diameter than the inner diameter W1 of the body portion 12A, whereby the thermally conductive fibers are easily along Extrusion direction. Thereby, the thermally conductive fibers can be more reliably aligned in the longitudinal direction of the preform 14.

For example, when the content of the thermally conductive fibers in the thermally conductive composition 12 is 15% by volume or more and 25% by volume or less, the extruder 13 preferably has a diameter W2 of the opening portion 12B of about 1.5 to 9.5 mm. In this case, by setting the diameter W2 of the opening 12B to 1.5 mm or more, it is possible to prevent the extrusion of the thermally conductive composition 12 by the extruder 13 from being difficult to extrude. Moreover, by setting the diameter W2 of the opening 12B to 9.5 mm or less, the alignment of the thermally conductive fibers is less likely to be disturbed, so that the thermal conductivity of the thermally conductive sheet 1 in the thickness direction can be further improved.

In the extruder 13, the cross-sectional shape of the opening portion 12B can be, for example, a circular shape, a triangular shape, a rectangular shape, or a square shape, and is preferably a rectangular shape or a square shape. The preform 14 has a columnar shape by forming the cross-sectional shape of the opening 12B into a rectangular shape or a square shape. Therefore, in the arranging step S22, a plurality of preforms 14 are arranged adjacent to each other in the direction orthogonal to the longitudinal direction, so that the plurality of arranged preforms 14 are arranged to be substantially orthogonal to the arrangement direction. When the laminated body 14A (hereinafter referred to as the laminated body 14A) formed in the direction is formed, a gap is unlikely to occur between the laminated bodies 14A. As a result, bubbles are less likely to be contained in the laminated body 14A, so that the main molded body 16 having more excellent flame retardancy can be obtained in the main molding step S23.

The preform 14 is oriented along the extrusion direction of the extruder 13 and has an elongated columnar shape, for example, an elongated rectangular columnar shape, an elongated triangular column shape, and an elongated cylindrical shape.

[Arrangement Step S22]

In the arranging step S22, for example, as shown in FIG. 5(B), FIG. 5(C), and FIG. 6, the plurality of pre-forms formed in the pre-forming step S21 are arranged adjacent to each other in the direction orthogonal to the longitudinal direction. The molded body 14 is molded to obtain a laminated body 14A. For example, in the arranging step S22, the preforms 14 are arranged in the specific mold frame 15, and the laminated body 14A in which the preforms 14 are arranged in a rectangular parallelepiped shape or a cubic shape is obtained. When the main molded body 16 is molded in the main molding step S23, the mold frame 15 is used as a fixing means for fixing the laminated body 14A, and the laminated body 14A is prevented from being largely deformed. The mold frame 15 is formed, for example, of metal.

[Formal molding step S23]

In the main molding step S23, for example, as shown in FIG. 5(D), the laminated body 14A obtained in the arranging step S22 is cured, as shown in FIG. 5(E) and FIGS. 7(A) and (B). The formed body 16 in which the preforms 14 constituting the laminated body 14A are integrated with each other is molded. The method of curing the laminated body 14A is, for example, a method of heating the laminated body 14A by a heating device or a method of heating and pressurizing the laminated body 14A by a heating and pressurizing device. In addition, when the acrylic resin is used as the curable resin composition constituting the thermally conductive composition 12, for example, the isocyanate compound can be contained in the thermally conductive composition 12, and the laminated body 14A can be cured at room temperature.

As a method of curing the laminated body 14A, a method of heating and pressurizing the laminated body 14A by a heating and pressurizing means, that is, a plurality of preforms constituting the laminated body 14A, when the laminated body 14A is cured is preferably used. The direction in which the longitudinal direction of the body 14 is orthogonal (vertical direction) is pressurized. By pressurizing the laminated body 14A as described above, the bubbles can be more reliably removed from the laminated body 14A, so that the formal forming step S23 can obtain a more excellent flame retardancy. Molded body 16.

In this manner, a plurality of columnar preforms are arranged in the longitudinal direction, and a plurality of preforms are integrally molded into a molded body, and are cut in a direction substantially perpendicular to the longitudinal direction of the main molded body. This makes the thermal conductivity of the thermally conductive sheet 1 in the thickness direction better.

[Examples] <4. Example>

Hereinafter, embodiments of the invention will be described. In the present embodiment, a polyoxynoxy resin composition containing thermally conductive fibers and thermally conductive particles was prepared, and the thermal conductivity in the thickness direction of the thermally conductive sheet obtained from the polyoxyxylene resin composition with respect to the compressibility was evaluated. Further, the thermal resistance at the time of maintaining the state of the compressed thermally conductive sheet was evaluated. In the present embodiment, the average fiber length of the thermally conductive fibers is a calculated value obtained by measuring each thermally conductive fiber by a microscope (manufactured by HiROX Co Ltd, KH7700), and the average particle diameter of the thermally conductive particles is determined by a particle size distribution meter. Measured value. Furthermore, the invention is not limited to the embodiments.

<The thermal conductivity of the thermal conductive sheet in the thickness direction with respect to the compression ratio> [Example 1]

In the first embodiment, as shown in Table 1, an oxidation of an average particle diameter of 5 μm obtained by coupling a thermally conductive particle with a decane coupling agent was carried out in a two-liquid addition reaction type liquid polyoxynoxy resin. A polyfluorene oxide resin composition was prepared by using 20.4% by volume of aluminum particles, 24% by volume of aluminum nitride particles having an average particle diameter of 1 μm, and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 50 μm as thermally conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in a manner of 6:4.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyfluorene hardened material was cut with an ultrasonic cutter to have a thickness of 2.0 mm to obtain a thermally conductive sheet.

[Embodiment 2]

In Example 2, as shown in Table 1, two blends were used in such a manner that the blend ratio of polyxanthine main agent A and hardener B (polyoxygen main component A: hardener B) was 55:45. A thermally conductive sheet was obtained in the same manner as in Example 1 except that the liquid addition reaction type liquid polyoxyl resin was used.

[Example 3]

In Example 3, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 5:5. A thermally conductive sheet was obtained in the same manner as in Example 1 except that the liquid addition reaction type liquid polyoxyl resin was used.

[Comparative Example 1]

In Comparative Example 1, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 3:7. A thermally conductive sheet was obtained in the same manner as in Example 1 except that the liquid addition reaction type liquid polyoxyl resin was used.

[Example 4]

In the fourth embodiment, as shown in Table 1, a thermally conductive sheet was obtained in the same manner as in Example 1 except that pitch-based carbon fibers having an average fiber length of 100 μm were used as the thermally conductive fibers.

[Example 5]

In Example 5, as shown in Table 1, it was used to blend the polyanthracene main agent A with the hardener B. In the same manner as in Example 4 except that the liquid-liquid addition-type liquid polyoxyl resin was blended in a ratio of 55:45 (the polyoxygen main component A: the curing agent B). Thermal sheet.

[Embodiment 6]

In Example 6, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 5:5. A thermally conductive sheet was obtained in the same manner as in Example 4 except for the liquid addition reaction type liquid polyoxyl resin.

[Comparative Example 2]

In Comparative Example 2, as shown in Table 1, two of them were blended in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 3:7. A thermally conductive sheet was obtained in the same manner as in Example 4 except for the liquid addition reaction type liquid polyoxyl resin.

[Embodiment 7]

In the same manner as in Example 1, except that the pitch-based carbon fibers having an average fiber length of 150 μm were used as the thermally conductive fibers, as shown in Table 1, a thermally conductive sheet was obtained.

[Embodiment 8]

In Example 8, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 55:45. A thermally conductive sheet was obtained in the same manner as in Example 7 except for the liquid addition reaction type liquid polyoxyl resin.

[Embodiment 9]

In Example 9, as shown in Table 1, two of them were blended in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 5:5. A thermally conductive sheet was obtained in the same manner as in Example 7 except for the liquid addition reaction type liquid polyoxyl resin.

[Comparative Example 3]

In Comparative Example 3, as shown in Table 1, two of them were blended in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 3:7. A thermally conductive sheet was obtained in the same manner as in Example 7 except for the liquid addition reaction type liquid polyoxyl resin.

[Embodiment 10]

In the example 10, as shown in Table 1, a thermally conductive sheet was obtained in the same manner as in Example 1 except that pitch-based carbon fibers having an average fiber length of 180 μm were used as the thermally conductive fibers.

[Example 11]

In Example 11, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 55:45. A thermally conductive sheet was obtained in the same manner as in Example 10 except for the liquid addition reaction type liquid polyoxyl resin.

[Embodiment 12]

In Example 12, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 5:5. A thermally conductive sheet was obtained in the same manner as in Example 10 except for the liquid addition reaction type liquid polyoxyl resin.

[Comparative Example 4]

In Comparative Example 4, as shown in Table 1, two of them were blended in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 3:7. A thermally conductive sheet was obtained in the same manner as in Example 10 except for the liquid addition reaction type liquid polyoxyl resin.

[Example 13]

In the same manner as in Example 1, except that the pitch-based carbon fibers having an average fiber length of 250 μm were used as the thermally conductive fibers, as shown in Table 1, a thermally conductive sheet was obtained.

[Embodiment 14]

In Example 14, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 55:45. A thermally conductive sheet was obtained in the same manner as in Example 13 except for the liquid addition reaction type liquid polyoxyl resin.

[Example 15]

In Example 15, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) was 5:5. A thermally conductive sheet was obtained in the same manner as in Example 13 except for the liquid addition reaction type liquid polyoxyl resin.

[Comparative Example 5]

In Comparative Example 5, as shown in Table 1, two blends were used in such a manner that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) was 3:7. A thermally conductive sheet was obtained in the same manner as in Example 13 except for the liquid addition reaction type liquid polyoxyl resin.

[Measurement of thermal conductivity]

Loads were applied to the thermally conductive sheets of Examples 1 to 15 and Comparative Examples 1 to 5 by the measurement method according to ASTM-D5470 (0.5, 1, 1.5, 2, 3, 4, 5, 6, 7.5 kgf/cm ^{2 ).} ) and measure the thermal conductivity. Further, the compression ratio of the thermally conductive sheet when the load was applied was set to a ratio at which the initial thickness of 2.0 mm was changed to 100%.

8 to 12 are graphs showing the thermal conductivity of the thermally conductive sheet with respect to the compression ratio when the carbon fiber lengths are 50 μm, 100 μm, 150 μm, 180 μm, and 250 μm, respectively. 13 to 16 show that the blending ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component A: hardener B) is 6:4, 55:45, 5:5, and The relative position of the thermal pad at 3:7 A graph of the thermal conductivity at the compression ratio. In the case where the polyoxyxyl main agent A: the hardener B is equal to 5:5, it has fluidity due to the uncured component, but in the case where the polyoxynium main agent A: the hardener B is 3:7 , completely hardened, so there is no fluidity, and the compressibility deteriorates.

As is clear from FIGS. 8 to 16 , by having a compression ratio of 40% or more, the step difference between the heat source and the heat radiating member is filled to improve the adhesion, and excellent thermal conductivity can be obtained. Moreover, it is understood that the compression ratio of 40% or more can be obtained by blending the polyanthracene main agent A and the hardener B (polyoxygen main agent A: hardener B) from 5:5 to 6:4. Thermal sheet. In addition, it is understood that the average fiber length of the thermally conductive fibers is 100 μm or more and 250 μm or less, and when the compression ratio is 40% or less, an excellent peak of thermal conductivity of 20 W/mK or more can be obtained.

<Thermal resistance when maintaining the state of the compressed thermally conductive sheet> [Example 16]

In the liquid-liquid addition-type liquid polyoxyl resin of the two-component addition type, 21% by volume of the alumina particles having an average particle diameter of 5 μm which is obtained by coupling treatment with a decane coupling agent as the thermally conductive particles, A polyxanthoxy resin composition was prepared by using 22% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 25% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as heat conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in such a manner as to be 55:45.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. Using ultrasound The cutter cuts the polysulfide hardened material to a thickness of 3.5 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more.

The initial thermal resistance was measured by sandwiching the thermally conductive sheet between the heat source and the heat dissipating member and applying a load of 0.5 kgf/cm ² to a constant thickness. The initial thermal resistance is 1.29K. Cm ² /W. Thereafter, the thermally conductive sheet was placed between a heat source and a heat dissipating member in a thermostatic chamber at 85 ° C, taken out after 1000 hours, and the thermal resistance was measured. The thermal resistance after 1000 hours is 1.20K. Cm ² /W. Therefore, the rate of change of thermal resistance after the initial and 1000 hours is -7%. The results of these measurements are shown in Table 2.

[Example 17]

In the same manner as in Example 16, except that the thickness was changed to 2.0 mm by the ultrasonic cutter, the thermally conductive sheet was obtained in the same manner as in Example 16. The thermally conductive sheet has a compression ratio of 40% or more.

The initial thermal resistance was measured by sandwiching the thermally conductive sheet between the heat source and the heat dissipating member and applying a load of 2.0 kgf/cm ² to a constant thickness. The initial thermal resistance is 1.04K. Cm ² /W. Thereafter, the thermally conductive sheet was placed between a heat source and a heat dissipating member in a thermostatic chamber at 85 ° C, taken out after 1000 hours, and the thermal resistance was measured. The thermal resistance after 1000 hours is 0.79K. Cm ² /W. Therefore, the rate of change of thermal resistance after the initial and 1000 hours is -25%. The results of these measurements are shown in Table 2.

[Embodiment 18]

In Example 18, 31% by volume of alumina particles having an average particle diameter of 5 μm which was obtained by coupling treatment with a decane coupling agent as a thermally conductive particle in a two-liquid addition reaction type liquid polyoxynoxy resin, 22% by volume of aluminum nitride particles having an average particle diameter of 1 μm, and as a thermally conductive fiber A polyoxyxylene resin composition was prepared by dispersing 16% by volume of pitch-based carbon fibers having an average fiber length of 150 μm.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in such a manner as to be 55:45.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 3.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more.

The initial thermal resistance was measured by sandwiching the thermally conductive sheet between the heat source and the heat dissipating member and applying a load of 2.0 kgf/cm ² to a constant thickness. The initial thermal resistance is 2.23K. Cm ² /W. Thereafter, the thermally conductive sheet was placed between a heat source and a heat dissipating member in a thermostatic chamber at 85 ° C, taken out after 1000 hours, and the thermal resistance was measured. The thermal resistance after 1000 hours is 2.16K. Cm ² /W. Therefore, the rate of change of thermal resistance after the initial and 1000 hours is -3%. The results of these measurements are shown in Table 2.

[Reference Example 1]

In Reference Example 1, a thermally conductive sheet having the same composition as that of Example 1 was used. The thermally conductive sheet was not sandwiched between the heat source and the heat dissipating member, a load of 0.5 kgf/cm ² was applied to the thermally conductive sheet, and the initial thermal resistance was measured. The initial thermal resistance is 1.31K. Cm ² /W. Thereafter, the thermally conductive sheet was placed in a thermostat at 85 ° C, taken out after 1000 hours, and the thermal resistance was measured. The thermal resistance after 1000 hours is 1.43K. Cm ² /W. Therefore, the rate of change of thermal resistance after the initial and 1000 hours is 9.2%. The results of these measurements are shown in Table 2.

[Reference Example 2]

In Reference Example 2, a thermally conductive sheet having the same composition as that of Example 2 was used. The thermally conductive sheet was not sandwiched between the heat source and the heat dissipating member, and a load of 2.0 kgf/cm ² was applied to the thermally conductive sheet, and the initial thermal resistance was measured. The initial thermal resistance is 1.0K. Cm ² /W. Thereafter, the thermally conductive sheet was placed in a thermostat at 85 ° C, taken out after 1000 hours, and the thermal resistance was measured. The thermal resistance after 1000 hours is 1.02K. Cm ² /W. Therefore, the rate of change of thermal resistance after the initial and 1000 hours is 2%. The results of these measurements are shown in Table 2.

Further, Fig. 17 is a graph showing the thermal resistance with respect to the elapsed time in a state in which the thermally conductive sheet of the embodiment 17 is sandwiched between the heat source and the heat dissipating member. The heat conductive sheet was sandwiched between the heat source and the heat dissipating member, and placed in a constant temperature bath at 85 ° C under a load of 2.0 kgf / cm ² , after 100 hours, 300 hours, 500 hours, and 750 hours. After taking out, the thermal resistance was measured separately. According to the graph shown in Fig. 17, the thermal resistance of the state in which the displacement is constant or maintained at a certain load is smaller than the load immediately after the application of the load. Moreover, it is understood that the thermal resistance is substantially constant after 800 hours have elapsed.

As shown in Table 2 and FIG. 17, it is understood that when the filler amount of the thermally conductive particles and the filler of the thermally conductive fiber is 70 vol% or less, excellent flexibility with a compression ratio of 40% or more can be obtained, so that The passage of time can improve the adhesion between the heat source and the heat dissipating member, and reduce the thermal resistance.

<About the influence of the thickness of the thermal conductive sheet>

Then, a thermally conductive sheet of a specific thickness was produced to measure the thermal conductivity and thermal resistance.

[Measurement of thermal conductivity]

A load (kgf/cm ² ) was applied to the thermally conductive sheet by the measurement method according to ASTM-D5470, and the thermal conductivity was measured. Further, the compression ratio of the thermally conductive sheet when the load was applied was set to a ratio at which the initial thickness was changed to 100%.

[Measurement of thermal resistance]

Using a thermal resistance measuring device (manufactured by Dexerials Co., Ltd.), the thermal conductive sheet was sandwiched between the heat source and the heat radiating member by 20 mm. For the sample, the thermal resistance (K.cm ² /W) was measured under the applied load (kgf/cm ² ). Further, the compression ratio of the thermally conductive sheet when the load was applied was set to a ratio at which the initial thickness was changed to 100%.

[Embodiment 19]

In Example 19, in the two-liquid addition reaction type liquid polyoxynoxy resin, 20.4% by volume of alumina particles having an average particle diameter of 5 μm which was obtained by coupling treatment with a decane coupling agent as thermally conductive particles were mixed. A polyfluorene oxide resin composition was prepared by using 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as thermally conductive fibers.

Two-liquid addition reaction type liquid polyanthracene resin is used for organic polyoxyl The alkane is used as a main component, and is blended so that the blend ratio of the polyxanthine main component A and the hardener B (polyoxygen main component A: hardener B) is 55:45.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 3.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. 18 to 21 and Table 3 show an applied load of 0.5 kgf/cm ² (compression ratio 4.893%), 1.0 kgf/cm ² (compression ratio 10.071%), 1.5 kgf/cm ² (compression ratio 20.158%), 2.0 kgf/ Thermal conductivity or thermal resistance at cm ² (compression ratio 26.036%) and 3.0 kgf/cm ² (compression ratio 46.728%).

[Example 20]

In the same manner as in Example 19, a thermally conductive sheet was obtained in the same manner as in Example 19 except that the polyfluorene cured product was cut with an ultrasonic cutter to a thickness of 2.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. 18 to 21 and Table 4 show an applied load of 0.5 kgf/cm ² (compression ratio 5.771%), 1.0 kgf/cm ² (compression ratio 10.795%), 1.5 kgf/cm ² (compression ratio 19.755%), 2.0 kgf/ Thermal conductivity or thermal resistance at cm ² (compression ratio 36.586%) and 3.0 kgf/cm ² (compression ratio 52.079%).

[Example 21]

In the same manner as in Example 19, a thermally conductive sheet was obtained in the same manner as in Example 19 except that the polyanion cured product was cut by an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. 18 to FIG. 21 and Table 5 shows load is applied to 0.5kgf / cm ² (compression rate ^{5.680%), 1.0kgf / cm 2} ( compression rate ^{8.295%), 1.5kgf / cm 2} ( compression ratio 15.470%), 2.0kgf / Thermal conductivity or thermal resistance at cm ² (compression ratio 25.480%) and 3.0 kgf/cm ² (compression ratio 43.961%).

[Example 22]

In the same manner as in Example 19, a thermally conductive sheet was obtained in the same manner as in Example 19 except that the polyfluorinated cured product was cut by an ultrasonic cutter to a thickness of 1.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. 18 to 21 and Table 6 show an applied load of 0.5 kgf/cm ² (compression ratio 6.501%), 1.0 kgf/cm ² (compression ratio 8.603%), 1.5 kgf/cm ² (compression ratio 15.055%), 2.0 kgf/ Thermal conductivity or thermal resistance at cm ² (compression ratio 23.978%), 3.0 kgf/cm ² (compression ratio 39.808%), 4.0 kgf/cm ² (compression ratio 50.901%).

[Example 23]

In the same manner as in Example 19, a thermally conductive sheet was obtained in the same manner as in Example 19 except that the polyanion cured product was cut by an ultrasonic cutter to a thickness of 1.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. 18 to 21 and Table 7 show an applied load of 0.5 kgf/cm ² (compression ratio 4.269%), 1.0 kgf/cm ² (compression ratio 7.649%), 1.5 kgf/cm ² (compression ratio 11.679%), 2.0 kgf/ Thermal conductivity or thermal resistance at cm ² (compression ratio 20.420%), 3.0 kgf/cm ² (compression ratio 38.141%), 4.0 kgf/cm ² (compression ratio 47.330%).

[Example 24]

In the same manner as in Example 19, a thermally conductive sheet was obtained in the same manner as in Example 19 except that the polyfluorinated cured product was cut by an ultrasonic cutter to have a thickness of 0.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. 18 to 21 and Table 8 show an applied load of 0.5 kgf/cm ² (compression ratio 5.761%), 1.0 kgf/cm ² (compression ratio 7.860%), 1.5 kgf/cm ² (compression ratio 8.648%), 2.0 kgf/ Cm ² (compression ratio 10.667%), 3.0 kgf/cm ² (compression ratio 15.892%), 4.0 kgf/cm ² (compression ratio 21.753%), 5.3 kgf/cm ² (compression ratio 29.821%), 6.0 kgf/cm ² (compression ratio 36.038%), thermal conductivity or thermal resistance at 7.5 kgf/cm ² (compression ratio 44.279%).

[Example 25]

In the two-component addition reaction type liquid polyoxynoxy resin, the aluminum oxide particles having an average particle diameter of 5 μm which is obtained by coupling treatment with a decane coupling agent as a thermally conductive particle are mixed with 20.4% by volume, A polyfluorene oxide resin composition was prepared by using 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as thermally conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in such a manner as to be 60:40.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 3.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. 22 to 25 and Table 9 show an applied load of 0.5 kgf/cm ² (compression ratio 5.522%), 1.0 kgf/cm ² (compression ratio 12.867%), 1.5 kgf/cm ² (compression ratio 33.780%), 2.0 kgf/ Cm ² (compression ratio 46.857%), 3.0 kgf/cm ² (compression ratio 59.113%), 4.0 kgf/cm ² (compression ratio 66.573%), 5.3 kgf/cm ² (compression ratio 72.782%), 6.0 kgf/cm ² (compression ratio 75.367%), 7.5 kgf/cm ² (compression ratio 77.601%), thermal conductivity or thermal resistance.

[Example 26]

In the same manner as in Example 25, a thermally conductive sheet was obtained in the same manner as in Example 25 except that the polyanion cured product was cut with an ultrasonic cutter to a thickness of 2.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. 22 to 25 and Table 10 show an applied load of 0.5 kgf/cm ² (compression ratio 6.042%), 1.0 kgf/cm ² (compression ratio 12.571%), 1.5 kgf/cm ² (compression ratio 31.371%), 2.0 kgf/ Cm ² (compression ratio 43.307%), 3.0 kgf/cm ² (compression ratio 53.652%), 4.0 kgf/cm ² (compression ratio 59.514%), 5.3 kgf/cm ² (compression ratio 66.962%), 6.0 kgf/cm ² (compression ratio 70.629%), thermal conductivity or thermal resistance at 7.5 kgf/cm ² (compression ratio 74.061%).

[Example 27]

In the same manner as in Example 25, a thermally conductive sheet was obtained in the same manner as in Example 25 except that the polyfluorene cured product was cut with an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. 22 to 25 and Table 11 show an applied load of 0.5 kgf/cm ² (compression ratio 4.800%), 1.0 kgf/cm ² (compression ratio 10.710%), 1.5 kgf/cm ² (compression ratio 19.467%), 2.0 kgf/ Cm ² (compression ratio 43.161%), 3.0 kgf/cm ² (compression ratio 53.111%), 4.0 kgf/cm ² (compression ratio 59.107%), 5.3 kgf/cm ² (compression ratio 68.042%), 6.0 kgf/cm ² (compression ratio: 71.279%), thermal conductivity or thermal resistance at 7.5 kgf/cm ² (compression ratio 73.934%).

[Example 28]

In the same manner as in Example 25, a thermally conductive sheet was obtained in the same manner as in Example 25 except that the polyanion cured product was cut with an ultrasonic cutter to a thickness of 1.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. 22 to 25 and Table 12 show an applied load of 0.5 kgf/cm ² (compression ratio 5.777%), 1.0 kgf/cm ² (compression ratio 12.835%), 1.5 kgf/cm ² (compression ratio 20.523%), 2.0 kgf/ Cm ² (compression ratio 34.738%), 3.0 kgf/cm ² (compression ratio 48.046%), 4.0 kgf/cm ² (compression ratio 57.129%), 5.3 kgf/cm ² (compression ratio 63.879%), 6.0 kgf/cm ² (compression ratio 66.955%), thermal conductivity or thermal resistance at 7.5 kgf/cm ² (compression ratio 71.815%).

[Example 29]

In the same manner as in Example 25, a thermally conductive sheet was obtained in the same manner as in Example 25 except that the polyfluorene cured product was cut by an ultrasonic cutter to a thickness of 1.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. 22 to 25 and Table 13 show an applied load of 0.5 kgf/cm ² (compression ratio 5.588%), 1.0 kgf/cm ² (compression ratio 10.313%), 1.5 kgf/cm ² (compression ratio 15.619%), 2.0 kgf/ Cm ² (compression ratio 36.487%), 3.0 kgf/cm ² (compression ratio 50.618%), 4.0 kgf/cm ² (compression ratio 58.540%), 5.3 kgf/cm ² (compression ratio 55.963%), 6.0 kgf/cm ² (compression ratio 59.207%), thermal conductivity or thermal resistance at 7.5 kgf/cm ² (compression ratio 64.443%).

As shown in FIG. 18 to FIG. 25, when the thickness is 3.0 mm or less, it is found that the compression ratio is 40% or more, and the heat resistance is 0.5 kgf/cm ² or more and the load range of 3 kgf/cm ² or less has a minimum value. Thermal sheet. The heat resistance of the thermal conductive sheet is in the range of 0.5 kgf/cm ² or more and 3 kgf/cm ² or less, which decreases with the application of the load, and increases after the minimum value is obtained, thereby, for example, electronic components on the substrate. When the heat transfer sheet and the heat radiating member are provided on the heating element, the heat generating body and the heat radiating member can be closely contacted with a small load, and excellent thermal conductivity can be obtained. Moreover, since it can be mounted on the substrate with a small load, the risk of damage of the substrate can be reduced.

<About the maximum compressive stress and residual stress of the thermal sheet>

Then, the maximum compression stress and residual stress of the thermally conductive sheet of a specific thickness were measured by blending the blend ratio of the polyxanthine main agent A and the hardener B at a specific ratio (polyoxygen main component A: hardener B).

[Measurement of Maximum Compressive Stress and Residual Stress]

The maximum compressive stress at 40% compression at a speed of 25.4 mm/min was measured on a 25 mm × 25 mm test piece by a tensile compression tester (Tensilon RTG1225 manufactured by A&D Co., Ltd.). Further, the residual stress was maintained for 10 minutes while being subjected to 40% compression. Further, in the case of compression at a speed slower than 25.4 mm/min, the maximum compressive stress was reduced as compared with the case of compression at a speed of 25.4 mm/min.

Test piece: 25mm × 25mm

Compression ratio: 40%

Test speed: 25.4mm/min

Test machine dynamometer: 2.5kN

Compression plate: metal

[Example 30]

In Example 30, in the two-liquid addition reaction type liquid polyoxynoxy resin, 20.4% by volume of alumina particles having an average particle diameter of 5 μm which was obtained by coupling treatment with a decane coupling agent as thermally conductive particles were mixed. A polyfluorene oxide resin composition was prepared by using 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as thermally conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in such a manner as to be 50:50.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 1.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 1000 N, and the residual stress after 10 minutes was 220 N.

[Example 31]

In the same manner as in Example 30, a thermally conductive sheet was obtained in the same manner as in Example 30 except that the polyanion cured product was cut with an ultrasonic cutter to have a thickness of 1.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 780 N, and the residual stress after 10 minutes was 204 N.

[Example 32]

In the same manner as in Example 30, a thermally conductive sheet was obtained in the same manner as in Example 30 except that the polyelectrolytic cured product was cut by an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 700 N, and the residual stress after 10 minutes was 197 N.

[Example 33]

In the same manner as in Example 30, a thermally conductive sheet was obtained in the same manner as in Example 30 except that the polyfluorene cured product was cut by an ultrasonic cutter to have a thickness of 3.0 mm. The thermal pad has 40% or more of the compression rate. Further, as shown in Table 14, the maximum compressive stress was 660 N, and the residual stress after 10 minutes was 178 N.

[Example 34]

In Example 34, in the two-liquid addition reaction type liquid polyoxynoxy resin, 20.4% by volume of alumina particles having an average particle diameter of 5 μm which was obtained by coupling treatment with a decane coupling agent as heat conductive particles were mixed. A polyfluorene oxide resin composition was prepared by using 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as thermally conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in such a manner as to be 55:45.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 1.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 980 N, and the residual stress after 10 minutes was 198N.

[Example 35]

In the same manner as in Example 34, a thermally conductive sheet was obtained in the same manner as in Example 34 except that the polyfluorinated cured product was cut by an ultrasonic cutter to have a thickness of 1.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 756 N, and the residual stress after 10 minutes was 188 N.

[Example 36]

In the same manner as in Example 34, a thermally conductive sheet was obtained in the same manner as in Example 34 except that the polyfluorinated cured product was cut by an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 680 N, and the residual stress after 10 minutes was 133 N.

[Example 37]

In the same manner as in Example 34, a thermally conductive sheet was obtained in the same manner as in Example 34 except that the polyanion cured product was cut by an ultrasonic cutter to have a thickness of 3.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 610 N, and the residual stress after 10 minutes was 124 N.

[Example 38]

In Example 38, in the two-liquid addition reaction type liquid polyoxynoxy resin, 20.4% by volume of alumina particles having an average particle diameter of 5 μm which was obtained by coupling treatment with a decane coupling agent as thermally conductive particles were mixed. A polyfluorene oxide resin composition was prepared by using 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm and 22.3% by volume of pitch-based carbon fibers having an average fiber length of 150 μm as thermally conductive fibers.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The hardener B) is blended in a manner of 57:43.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. Using ultrasound The cutter cuts the polyoxygen hardened material to a thickness of 1.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 932 N, and the residual stress after 10 minutes was 172 N.

[Example 39]

In the same manner as in Example 38, a thermally conductive sheet was obtained in the same manner as in Example 38 except that the polyfluorinated cured product was cut with an ultrasonic cutter to a thickness of 1.5 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 712 N, and the residual stress after 10 minutes was 156 N.

[Embodiment 40]

In the same manner as in Example 38, a thermally conductive sheet was obtained in the same manner as in Example 38 except that the polyanion cured product was cut by an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 645 N, and the residual stress after 10 minutes was 120 N.

[Example 41]

In the same manner as in Example 38, a thermally conductive sheet was obtained in the same manner as in Example 38 except that the polyanthracene hardened material was cut by an ultrasonic cutter to have a thickness of 3.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 570 N, and the residual stress after 10 minutes was 111 N.

[Example 42]

In the liquid-liquid addition-type liquid polyoxyl resin of the two-component addition type, 20.4% by volume of alumina particles having an average particle diameter of 5 μm which is obtained by coupling treatment with a decane coupling agent as heat conductive particles, 24.0% by volume of aluminum nitride particles having an average particle diameter of 1 μm, and as thermal conductivity A polydecane resin composition was prepared by using a pitch-based carbon fiber having an average fiber length of 150 μm of 22.3% by volume.

The two-liquid addition reaction type liquid polyoxynoxy resin uses an organic polyoxyalkylene as a main component, and a blend ratio of the polyxanthine main agent A and the hardener B (polyoxygen main component) A: The cured product B) was blended in such a manner as to be 60:40.

The obtained polyoxynoxy resin composition was extrusion-molded in a hollow square column mold (35 mm × 35 mm) to form a 35 mm square polyoxymethylene molded body. The polyoxynitride molded article was heated at 100 ° C for 6 hours in an oven to prepare a polyoxygenated hardened product. The polyelectrolytic hardened material was cut with an ultrasonic cutter to have a thickness of 1.0 mm to obtain a thermally conductive sheet. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 910 N, and the residual stress after 10 minutes was 154 N.

[Example 43]

In the same manner as in Example 42, except that the thickness of the polyfluorene cured product was changed to 1.5 mm by an ultrasonic cutter, the thermally conductive sheet was obtained. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 690 N, and the residual stress after 10 minutes was 147 N.

[Example 44]

In the example 44, a thermally conductive sheet was obtained in the same manner as in Example 42 except that the polyfluorene cured product was cut with an ultrasonic cutter to a thickness of 2.0 mm. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 590 N, and the residual stress after 10 minutes was 90N.

[Example 45]

In the same manner as in Example 42, except that the polyfluorene cured product was cut with an ultrasonic cutter to a thickness of 3.0 mm, a thermally conductive sheet was obtained. The thermally conductive sheet has a compression ratio of 40% or more. Further, as shown in Table 14, the maximum compressive stress was 543 N, and the residual stress after 10 minutes was 85 N.

As shown in Table 14, it is understood that when the thickness is 3.0 mm or less, the maximum compressive stress at 40% compression at a speed of 25 mm/min or less is 1000 N or less, and 40% compression is performed at a speed of 25 mm/min or less. The residual stress at the time of holding for 10 minutes under 40% compression was 220 N or less. When the 40% compression is performed at a speed of 25 mm/min or less, the maximum compressive stress is 1000 N or less, whereby the load on the substrate is reduced at the time of installation, so that the risk of damage of the substrate can be reduced. Further, 40% compression is performed at a speed of 25 mm/min or less, and the residual stress at a temperature of 40% compression for 10 minutes is 220 N or less, whereby the stress applied to the substrate can be reduced during long-term use.

Claims (41)

A thermally conductive sheet comprising a curable resin composition, a thermally conductive fiber, and thermally conductive particles, having a compression ratio of 40% or more, and a thickness of the thermally conductive sheet of 1 mm or more. The thermally conductive sheet according to claim 1, wherein the curable resin composition is a two-liquid addition reaction type liquid polyfluorene resin of a polyxanthine main agent and a hardener, and the polyxanthene main agent The blending ratio with the hardener (polyoxygen main: hardener) is 5:5 to 6:4. The thermally conductive sheet according to claim 1 or 2, wherein the thermally conductive fibers have an average fiber length of 50 μm or more and 250 μm or less. The thermally conductive sheet according to claim 1 or 2, which has a thermal conductivity peak of 15 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet of claim 3, which has a thermal conductivity of 15 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet according to claim 1 or 2, which has a thermal conductivity peak of 20 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet according to claim 1 or 2, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 3, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 4, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. A thermally conductive sheet according to claim 1 or 2, which is attached to the length of the column The columnar cured product is formed by cutting the columnar cured product in a vertical direction, and the thermally conductive polymer and the thermally conductive composition of the thermally conductive particles are extrusion-molded. A thermally conductive sheet comprising a curable resin composition, a thermally conductive fiber, and thermally conductive particles, wherein the thermally conductive particles and the thermally conductive fibers are filled in an amount of 70 vol% or less, and the thermally conductive sheet has a thickness of 1 mm or more. A device in which a thermally conductive sheet according to any one of claims 1 to 11 is sandwiched between a heat source and a heat dissipating member. The device of claim 12, wherein the thermal resistance of the thermally conductive sheet is reduced by 3% or more compared to an initial value obtained by being sandwiched between the heat source and the heat dissipating member. A thermally conductive sheet comprising a curable resin composition, a thermally conductive fiber, and thermally conductive particles, wherein a compression ratio is 40% or more, and a heat resistance of 0.5 kgf/cm ² or more and a load range of 3 kgf/cm ² or less has a minimum value. The thickness of the thermally conductive sheet is 1 mm or more. The thermally conductive sheet of claim 14 has a thickness of 3.0 mm or less and a maximum compressive stress of 1000 N or less when subjected to 40% compression at a speed of 25 mm/min or less. The thermally conductive sheet of claim 14 or 15 has a thickness of 3.0 mm or less, 40% compression at a speed of 25 mm/min or less, and a residual stress of 220 N at 40% compression for 10 minutes. the following. The thermally conductive sheet of claim 14 or 15, wherein the curable resin composition is a two-liquid addition reaction type liquid polyoxyl resin of a polyoxon main agent and a hardener, and the polysiloxane The blending ratio of the main agent to the hardener (polyoxygen main agent: hardener) is 5:5 to 6:4. The thermally conductive sheet of claim 14 or 15, wherein the thermally conductive fibers have an average fiber length of 50 μm or more and 250 μm or less. The thermally conductive sheet of claim 17, wherein the thermally conductive fiber has an average fiber length of 50 μm or more and 250 μm or less. The thermally conductive sheet of claim 14 or 15 which has a thermal conductivity peak of 15 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet of claim 17 which has a thermal conductivity of 15 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet of claim 18, which has a thermal conductivity of 15 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet of claim 14 or 15 which has a thermal conductivity peak of 20 W/mK or more at a compression ratio of 40% or less. The thermally conductive sheet of claim 14 or 15, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 17, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 18, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 20, wherein the thermally conductive particles and the thermally conductive fibers are contained in an amount of 70 vol% or less. The thermally conductive sheet of claim 14 or 15, which is formed by cutting a columnar hardened material in a direction substantially perpendicular to a longitudinal direction of the column, the columnar cured product containing the hardenability The resin composition, the thermally conductive fiber, and the thermally conductive composition of the thermally conductive particles are extrusion molded. A device in which a heat conductive sheet according to any one of claims 14 to 28 is sandwiched between a heat source and a heat radiating member. The device of claim 29, wherein the thermal resistance of the thermally conductive sheet is reduced by 3% or more compared to an initial value obtained by being sandwiched between the heat source and the heat dissipating member. A method for producing a thermally conductive sheet, comprising the steps of: forming a step of extruding a thermally conductive composition comprising a curable resin composition, a thermally conductive fiber, and thermally conductive particles; and a cutting step, which is relative to the column Cutting the extruded columnar hardened material in a direction perpendicular to the longitudinal direction to obtain a thermally conductive sheet; in the cutting step, cutting into a specific thickness to make 40% compression at a speed of 25 mm/min or less The maximum compressive stress is 1000 N or less; the thickness of the thermally conductive sheet is 1 mm or more. The method for producing a thermally conductive sheet according to claim 31, wherein in the cutting step, the thickness is cut to a specific thickness so that 40% compression is performed at a speed of 25 mm/min or less and maintained for 10 minutes under 40% compression. The residual stress at the time is 220 N or less. The method for producing a thermally conductive sheet according to claim 31, wherein the cutting step is cut to a specific thickness so that a heat resistance of 0.5 kgf/cm ² or more and 7.5 kgf/cm ² or less is 2.0. K. Cm ² /W or less. The method for producing a thermally conductive sheet according to claim 31, wherein the cutting step is performed to a thickness of 3.0 mm or less. The method for producing a thermally conductive sheet according to claim 31 or 32, further comprising a pressurizing step of pressurizing the thermally conductive sheet cut in a substantially perpendicular direction, and pressurizing in the pressurizing step , the thermal resistance of 0.5kgf / cm ² or more and 7.5kgf / cm ² or less load range of 2.0K. Cm ² /W or less. The method for producing a thermally conductive sheet according to claim 35, wherein in the cutting step, the thickness is cut to a thickness of 3.0 mm or less. The method for producing a thermally conductive sheet according to claim 35, wherein in the pressurizing step, the pressurization is performed at a pressure of 0.1 MPa or more and 30 MPa or less. The method for producing a thermally conductive sheet according to claim 35, wherein in the pressurizing step, the pressurization is performed at a temperature of not less than room temperature and not more than 140 °C. A thermally conductive sheet obtained by the method for producing a thermally conductive sheet according to any one of claims 31 to 38. A device for clamping a heat conductive sheet of claim 39 between a heat source and a heat dissipating member. The device of claim 40, wherein the thermal resistance of the thermally conductive sheet is reduced by 3% or more compared to an initial value obtained by being sandwiched between the heat source and the heat dissipating member.